1. Field of the Invention
The present invention is related to composite structures manufacturing methods and apparatus for practicing such methods. More particularly, the present invention is directed to a method and apparatus for making pre-impregnated multi-filament tows or rovings into a flat ribbon of predetermined thickness and width that can be processed through a delivery head and placed onto a mandrel surface for forming tubular articles.
2. Description of Background and Other Information
In present fiber placement systems, fibrous rovings or tows, impregnated with a thermosetting resin, are wound in a helical pattern in a number of superimposed layers onto a mandrel to produce a tubular article.
Various methods are known in the art of manufacturing composite structures, including hand lay-up, automated tape lay-up, filament winding, and fiber placement.
The present invention applies to the area of fiber placement. Examples of such systems can be found in U.S. Pat. Nos. 4,699,683 and 4,877,471, assigned to Boeing Company, Seattle, Wash. In addition, commonly assigned copending application Ser. No. 07/275,313, filed Nov. 23, 1988, now U.S. Pat. No. 5,045,147, discloses a fiber placement system.